Expansible pressure-sealing device

ABSTRACT

An expansible pressure sealing device for enclosing a stream of liquid from contact with the atmosphere as the stream is poured into a chamber. Intended particularly for enclosing a stream of metal as it is poured from a ladle into a vacuum degassing chamber. Device includes an axially movable tube positioned in the inlet of the chamber, and inner and outer spaced-apart concentric bellows around the tube. Pressure can be applied to the space between the two bellows for expanding them and thus uniformly moving a flange at the top of the tube into sealing engagement with the pouring vessel.

Sept.5, 1972 United States Patent Grosko 8/1969 Munton R [54] EXPANSIBLE PRESSURE-SEALING DEVICE [72] Inventor:

Primary Examiner-J. Spencer Overholser Assistant Examiner-John E. Roethel Attorney-Walter P. Wood John A. Grosko, West Mifflin, Pa.

[73] Assignee: United States Steel Corporation [22] Filed:

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UNITED STATES PATENTS 3,563,938 Ga1iucci.................141/31l X 1 Claim, 1 Drawing Figure ATMOSPHERE VACUUM SOURCE COMPRESSED AIR SOURCE 38 PKTENTEDSEP 5:912

INVENTOR. JOHN A. GROSKO Wm fil me ATMOSPHERE VA CUUM SOURCE COMPRESSED A ll? SOURCE Attorney EXPANSIBLE PRESSURE-SEALING DEVICE This invention relates to an improved expansible pressure-sealing device.

Although my invention is not thus limited, my sealing device is particularly useful as a means through which liquid metal can be teemed into a vacuum degassing chamber. In a conventional in-line degassing operation, liquid metal is teemed through an outlet in the bottom of a ladle or the like into a chamber which is under vacuum. To preserve the vacuum, it is of course necessary to enclose the stream of metal as it flows from the ladle outlet into the vacuum chamber. Reference can be made to my earlier application Ser. No. 781,929, filed Dec. 6, 1968, (now US. Pat. No. 3,550,924) for a showing of one arrangement of this type.

An object of the present invention is to provide an improved expansible pressure sealing device, particularly adapted for use with a vacuum degassing chamber, which device is of simple construction, yet affords a uniform tight seal between an inlet and an outlet thereabove.

A more specific object is to provide an improved sealing device which includes an axially movable inlet tube and a concentric double-bellows surrounding the tube for forcing the top of the tube into an evenly applied engagement with an outlet plate or the like thereabove.

In the drawing:

The single FIGURE is a partly diagrammatic vertical sectional view of my sealing device as applied to a ladle and degassing chamber.

The drawing shows portions of a conventional ladle and degassing chamber 12. The ladle includes a metal shell 13, a refractory lining 14 and a nozzle 15 in its bottom wall. An orifice plate 16 is fixed to the underside of the nozzle. I show the ladle equipped with both a stopper rod 17 and a slidable gate 18 for controlling discharge of material through nozzle 16, but only one of these devices actually is necessary. I show the gate in a position in which an orifice 19 therein is aligned with the orifice in plate 16 to permit teeming. To close the outlet from the ladle, I move either a blank gate or a blank portion of the same gate into alignment with the orifice in plate 16, or I lower the stopper on rod 17 into engagement with the nozzle.

In accordance with my invention, I position an axially movable refractory tube 22in the inlet opening 23 of the degassing chamber 12. The outer portion of tube 22 carries a metal sleeve 24, and the outer end carries a metal flange 25. I show the flange as carrying guides 26 which receive the slidable gate 18 as in my aforementioned application, but these guides are optional. I mount spaced-apart inner and outer expansible metal bellows 27 and 28 around tube 22 concentric with each other and with the tube in the space between the top of the degassing chamber 12 and the underside of flange 25. I attach the bottom and top edges of both bellows to annular plates 29 and 30 respectively, which I bolt to the degassing chamber 12 and to flange 25. Preferably I encase the bellows in inner and outer telescoping metal shields 31 and 32 to protect the bellows from excessive heat. The shields are attached to the circumferential edges of plates 29 and 30.

The bottom annular plate 29 has drilled passages 35 which communicate with the space between the inner and outer bellows 27 and 28. I connect a pipe 36 with the passages 35, which pipe has branches 36a and 36b. Branch 36a extends to a three-way valve 37, which has connections leading to a source 38 of compressed air or other gas and to an exhaust 39. A pressure regulator 40 may be connected between valve 37 and the compressed air source 38. Branch 36b extends to a two-way valve 41 which has a connection leading to a vacuum source 42. I have not shown the valves in detail since they may be of well-known conventional construction.

In operation, I position a ladle 10 of liquid metal over the degassing chamber 12, using conventional handling equipment. Initially the three-way valve 37 connects pipe 36 to the exhaust 39, the two-way valve 41 is closed, and gate 18 or stopper rod 17 closes the nozzle 15. When the ladle reaches the proper position, I operate the three-way valve 41 to connect pipe 36 to the compressed air source 38. The resulting pressure expands the bellows 27 and 28 and thus raises flange 25 evenly throughout its area into contact with the underside of gate 18. Guides 26 receive the gate, whereafterl evacuate chamber 12. Next I open nozzle 15 to teem the contents of the ladle into the chamber while tube 22 encloses the pouring stream against contact with the atmosphere. At the conclusion of the teeming operation, I operate the three-way valve 37 to connect pipe 36 again with the exhaust 39. The loss of pressure contracts the bellows and lowers flange 25. To lower the flange still farther, I close the three-way valve 37 and open the two-way valve 41, thereby connecting pipe 36 to the vacuum source 42. The further loss of pressure at the bellows further contracts them.

From the foregoing description, it is seen that my invention affords an expansible pressure sealing device which is simple mechanically yet always insures that parts are sealed evenly throughout their areas of contact. Although I show the device applied to a degassing chamber which receives liquid metal from a ladle, it is apparent the device has broader utility. For example, it may be used wherever a pouring stream of metal is to be enclosed from contact with the atmosphere, as in pouring metal into or out of a tundish.

I claim:

1. The combination, with a vacuum degassing chamber for liquid metal, said chamber having an inlet for receiving a stream of liquid metal, of a sealing device for enclosing said stream against contact with the atmosphere, said device comprising:

a tube positioned in said inlet for axial movement;

a flange fixed to the outer end of said tube for contacting the surface of a pouring vessel in sealing engagement therewith;

spaced-apart inner and outer expansible bellows around said tube concentric with each other and with said tube;

lower and upper annular plates attached to the respective ends of both said bellows and to said chamber and to said flange;

a three-way valve having connections for selectively admitting gas under pressure into the space between said bellows to expand the bellows or relieving said space to contract said bellows;

means for connecting the space between said bellows to a source of vacuum; and

inner and outer telescoping shields encasing said bellows. 

1. The combination, with a vacuum degassing chamber for liquid metal, said chamber having an inlet for receiving a stream of liquid metal, of a sealing device for enclosing said stream against contact with the atmosphere, said device comprising: a tube positioned in said inlet for axial movement; a flange fixed to the outer end of said tube for contacting the surface of a pouring vessel in sealing engagement therewith; spaced-apart inner and outer expansible bellows around said tube concentric with each other and with said tube; lower and upper annular plates attached to the respective ends of both said bellows and to said chamber and to said flange; a three-way valve having connections for selectively admitting gas under pressure into the space between said bellows to expand the bellows or relieving said space to contract said bellows; means for connecting the space between said bellows to a source of vacuum; and inner and outer telescoping shields encasing said bellows. 